/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.solr.core;

import org.apache.solr.search.SolrIndexSearcher;
import org.apache.solr.util.plugin.NamedListInitializedPlugin;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 *
 */
public interface SolrEventListener extends NamedListInitializedPlugin {
	static final Logger log = LoggerFactory.getLogger(SolrCore.class);

	public void postCommit();

	public void postSoftCommit();

	/**
	 * The searchers passed here are only guaranteed to be valid for the
	 * duration of this method call, so care should be taken not to spawn
	 * threads or asynchronous tasks with references to these searchers.
	 * <p/>
	 * Implementations should add the
	 * {@link org.apache.solr.common.params.EventParams#EVENT} parameter and set
	 * it to a value of either:
	 * <ul>
	 * <li>{@link org.apache.solr.common.params.EventParams#FIRST_SEARCHER} -
	 * First Searcher event</li>
	 * <li>{@link org.apache.solr.common.params.EventParams#NEW_SEARCHER} - New
	 * Searcher event</li>
	 * </ul>
	 * 
	 * Sample:
	 * 
	 * <pre>
	 * if (currentSearcher != null) {
	 * 	nlst.add(CommonParams.EVENT, CommonParams.NEW_SEARCHER);
	 * } else {
	 * 	nlst.add(CommonParams.EVENT, CommonParams.FIRST_SEARCHER);
	 * }
	 * 
	 * </pre>
	 * 
	 * @see org.apache.solr.core.AbstractSolrEventListener#addEventParms(org.apache.solr.search.SolrIndexSearcher,
	 *      org.apache.solr.common.util.NamedList)
	 * 
	 * @param newSearcher
	 *            The new {@link org.apache.solr.search.SolrIndexSearcher} to
	 *            use
	 * @param currentSearcher
	 *            The existing {@link org.apache.solr.search.SolrIndexSearcher}.
	 *            null if this is a firstSearcher event.
	 * 
	 */
	public void newSearcher(SolrIndexSearcher newSearcher,
			SolrIndexSearcher currentSearcher);

}
